When a person suffers from a hearing loss where is not possible to transform sound signals into signals in an audible frequency range using a hearing instrument, a cochlear implant may be used for electrical stimulation to the auditory nerve in the inner ear. Both children and adults with a severe to profound hearing loss, who cannot be helped with ordinary hearing instruments, may be helped with cochlear implants. Cochlear Implants (CI) are today a very successful treatment for people with profound hearing losses. CI's operates by stimulating the auditory nerve fibres electrically. The cochlea itself is a conical helical chamber of bone including the fluid-filled scala tympani and scala vestibuli separated by the basilar membrane on which sound induced mechanical waves travel. The base of the cochlea, nearest the round and oval windows, is relatively stiff and responsive to high frequencies; the apex of the cochlea is tuned to receive lower frequencies, tonotopic organisation, when functioning, hair cells respond to the motion of fluid to generate electrical signals. Generally, the electrode array is implanted into the scala tympani.
A Cochlear Implant typically includes i) an external part for picking up and processing sound from the environment, and for determining sequences of pulses for stimulation of the electrodes in dependence on the current input sound, ii) a (typically wireless, e.g. inductive) communication link for simultaneously transmitting information about the stimulation sequences and for transferring energy to iii) an implanted base part allowing the stimulation to be generated and applied to a number of electrodes, which are implantable in different locations of the cochlea allowing a stimulation of different frequencies of the audible range. Such systems are e.g. described in U.S. Pat. No. 4,207,441 and in U.S. Pat. No. 4,532,930.
The CI electrode may comprise multi-electrode array e.g. in the form of a carrier comprising a multitude of electrodes adapted for being located in the cochlea in proximity of an auditory nerve of the user. The carrier is preferably made of a flexible material to allow proper positioning of the electrodes in the cochlea such that the electrodes may be inserted in cochlea of a recipient. Preferably, the individual electrodes are spatially distributed along the length of the carrier to provide a corresponding spatial distribution along the cochlear nerve in cochlea when the carrier is inserted in cochlea.
If the user have residual hearing in one ear, a cochlear implant at one ear may be combined with a hearing device providing an acoustic signal at the ear with residual hearing may be provided, e.g. as disclosed in US 2010/030012.
One way of establishing a hearing system having an cochlear implant is to use an implantable base part and two electrodes, each electrode configured to be implanted into a respective cochlear, wherein the base part is to be implanted near one ear, and the first electrode is to be implanted into the proximal cochlear while the other electrode is implanted into the distal cochlear. In this configuration, only one major part is to be implanted. In order to provide a binaural signal to the user, one external device having a microphone system and a transmit device is positioned at the ear of the distal cochlear, and another external device having a microphone system and a receive device is positioned at the ear of the proximal cochlear may be provided. The two external devices may then be connected via a wire transferring signals between the two devices, primarily from the distal device to the proximal device. The device at the proximal cochlear then processes the received signal before transferring it to the implanted base unit. This system is cumbersome, and users have complained about the wired connection.
Hence, an improved hearing system would be advantageous, and in particular, a more efficient hearing system with wireless connection between an implanted device and an external device and between the external device and an additional second external device would be advantageous.
In a system providing acoustic signal to the ear canals of a user, synchronization between a first auditory prosthesis and a second auditory prosthesis of a bilateral auditory prosthesis system is discussed in US 2012/224705. In this system, a primary wireless communications channel, usable for synchronizing the first and second prostheses, may be disabled to, for example, conserve power.
It is an object of the present disclosure to provide at least an alternative to the prior art.